Fluid actuated hammer

ABSTRACT

A hollow central member is coupled to a tube to be driven into the ground. A driving mechanism includes a cylinder and piston surrounding the central member and a ram secured to the piston by a piston rod. The ram is reciprocated along the central member. A guide rod connected to the cylinder slides in a bore in the ram to prevent relative rotational movement between the cylinder and the ram. Air is delivered to the cylinder to raise and drive the ram downwardly. Means are provided for transferring the impact of the ram to the tube being driven.

United States Patent 1191 Cook July 22, 1975 [54] FLUID ACTUATED HAMMER3,583,501 6/1971 Aalund 173/78 X [76] Inventor: Allen B. Cook, 2121 W.38th Ave.,

Vancouver, 3 C Przmary Exammer-Frank L. Abbott AssistantExam'in'er-William F. Pate, Ill [22] Flled? 1973 Attorney, Agent,- '0rFirm-Seed, Berry, Vernon & 21' 1 Appl. NO.I 352,556 Bflynham RelatedU.S. Application Data [63] Continuation-impart of Ser. No. 212.957. Dec.28. [57] I ABSTRACT 1971, abandoned. A hollow central member is coupledto a tube to be driven into the gr ound. A driving mechanism includesU.S- Cla cylinder surrounding the central memh r Cl. and a ram ecured tothe piston a piston rod The 1 Fleld of Search ram is reciprocated alongthe central member. A 91/216 217 guide rod connected to the cylinderslides in a bore in 1 the ram to prevent relative rotational movementbe- Referemes Clted tween the cylinder and the ram. Air is delivered tothe UNITED STATES PATENTS cylinder to raise and drive the ramdownwardly. 2.706,}03 4/1955 Stambaugh et al. 91/216 B ux Means areProvided for transferring the impact of the 2,988,158 6/1961 Baldwin173/125 ram to the tube being driven- 3,524,5l 1 8 1970 K1 173 78 X 0911970 sai v i 1. 1 73/72; 13 l 7 Drawmg Flgures FLUID ACTUATED HAMMERThis application is a continuation-in-part of my US. patent applicationSer. No. 212,957, filed Dec. 28, 1971, now abandoned.

FIELD OF THE INVENTION This invention relates to apparatus for drivingopenended tubes into the ground while simultaneously permitting theremoval of materials from within the driven tube. Particularly, theinvention pertains to fluidactuated devices for accomplishing thispurpose.

DESCRIPTION OF THE PRIOR ART US. Pat. No. 3,474,870 discloses anapparatus for driving open tubes into the ground while allowing removalof materials from within the driven tube. The apparatus, although highlyefficient, is quite bulky and difficult to maneuver and requiresseparate, independent guide rods for maintaining the ram on the driventube.

SUMMARY OF THE INVENTION It is an object of this invention to provide anapparatus for driving an open tube into the ground while si multaneouslyallowing removal of debris from within the tube and wherein theapparatus is guided solely by a central member aligned with the driventube.

It is another object of this invention to provide a tube drivingapparatus of the type described above wherein a ram reciprocates on acentral member and impact loads from the ram are delivered throughvarious means which also align the central member with the tube beingdriven.

Basically, the invention accomplishes these objects by providing ahollow central member which supports a driving mechanism. The drivingmechanism includes a piston and cylinder which surround the centraltube. A piston rod is secured to the piston and, at its opposite end, isconnected to a ram. Impact forces from the ram can be passed to thedriven tube at either end of the hollow central member. One aligningmeans includes an internal shoulder on the central member, anotherincludes a threaded connection, used particularly when pulling pipe outof the ground. Another aligning means includes a slip-on collar. Stillanother includes an internal conventional half-coupling. Air supplymeans controls the flow and direction of air to the cylinder so as toreciprocate the ram for imparting an impact to the driven tube.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation with partsbroken away for clarity of a driving apparatus embodying the principlesof the invention.

FIGS. 2-4 are operational schematics. FIG. 2 illustrates the position ofthe ram at the moment of impact on the bottom of its stroke. FIG. 3illustrates the ram being raised in preparation for the next stroke.FIG. 4 illustrates the position of the ram as it reaches the top of itsstroke and begins to be propelled downwardly again.

FIG. 5 is an isometric of the hammer shown in FIG.

FIG. 6 is a fragmentary isometric with parts broken away for clarityillustrating a modified form of a hammer.

FIG. 7 is a longitudinal section of another embodiment showing inaddition two styles of driven pipe connection, styles A and B.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As best shown in FIG.1, the fluid-actuated hammer includes a cylindrical, hollow centralmember 10 having an upper flange 12 and a lower flange 14. The flangesare welded or otherwise sufficiently securely fastened to the centralmember to absorb impacts. An additional flange 13 is provided fordriving the central member upwardly. A driving mechanism 16 is securedto the hollow central member and includes a ram 18. The ram is drivenagainst the lower flange 14 or to suitable means to force the centralmember downwardly. The central member is also provided with means 20 foraligning the central member with the driven tube and suitable fortransferring the impact from the central member to the tubing or casingT to be driven into the ground. An air supply means 21 delivers air inalternate directions to the cylinder to reciprocate the ram. Theapparatus can be 'lifted and positioned over the tube to be driven byconventional hoisting apparatus secured to a pair of diametricallyopposed ears 23.

The driving mechanism 16 includes a cylinder 22 surrounding the centralmember 10. The cylinder is provided with upper and lower air passages 24and 26, respectively. Between the central member and the cylinder ismounted a slidable piston 28 which is sealed against the outer surfaceof the central member and inner surface of the cylinder by suitableO-ring seals 30.

a The piston divides the interior of the cylinder into an upper chamber32 and a lower chamber 34. Integrally formed on the piston 28 is atubular piston rod 36. The ram is integrally formed on the opposite endof the piston rod. Suitable seals 38 seal the lower end of the cylinderaround the piston rod 36. Seals 39 seal the upper end of the cylinderaround the central member 10.

The surface area of the piston 28 exposed to the lower chamber 34 isless than the surface area of the piston exposed to the upper chamber32. Thus air introduced simultaneously through the passages 24 and 26will produce a downward movement of the ram since greater force will beapplied to the top of piston 28 than to the bottom.

The ram is provided with a longitudinal bore 40 which slidable receivesa guide bar 42 that is secured to the cylinder 22. The guide barprevents the ram from rotating relative to the cylinder 22.

The preferred embodiment illustrates a configuration best adapted forpulling the tube and for this purpose the tube T is provided withexterior threads 44. The aligning means 20 in this embodiment includesinterior threads 46 in the lower terminal end of the hollow centralmember 10 which engage the threads 44. In soft soils this configurationcan also be used for driving the tube T. The tubing member T istherefore recessed as at 48 to provide an abutment surface against whichthe lower end of the central member rests so that all of the impact isnot taken solely by the threads 44 and 46. In most applications thetubing T will be more adequately protected when being driven such as bythe provisions of an'external collar similar to 20a (FIG. 6) or aconventional internal half-coupling, or the like.

The air supply means 21 includes an inlet pipe 50 coupled to an airconduit 52 which connects with the passage 24 and 26. A valve 54 fordelivering the air in various sequences includes an exhaust port 56, anintake port 58 and a valve block 60 positionable alternately to blockthe intake port 58 and interconnect passage 24 and exhaust port 56 orblock exhaust port 56 and interconnect intake port 58 with air passage24.

Movement of the valve 60 into the desired positions is I accomplished bya valve actuating mechanism 62.

The valve actuating mechanism 62 includes a rigid rod 64 secured to theram 18. The rigid rod is provided with an upper cam 66 and a lower cam68. Valve actuators 70 and 71 are rigidly secured to a shaft 72 that issecured to the valve block 60. The shaft 72 is mounted for oscillatorymovement within the valve 54. As best shown in FIG. 5, the upper andlower cams are offset transversely on the rigid rod 64 and are alignedrespectively with the valve actuators 70 and 71. Thus, upward movementof the ram will bring the lower cam 68- but rather the valve block willbe rotated prior to that time so that the piston is decelerated andreverses direction prior to impacting. On the downward stroke it isgenerally desired that the ram impact the flange 14. On some occasions,however, when it is desired to drive the central member upwardly toremove the tube T from a hole, the positions of the cams are arranged toeliminate impact on the downward stroke.

To best illustrate the operation of the ram, reference is made to FIGS.2 4. In FIG. 2 the ram is at the bottom of its downward stroke and hasjust impacted against the flange 14 moving the driven tube the distanceequal to movement of the central member from the phantom line positionas illustrated. Just at the moment of impact the upper cam 66 moves thevalve actuator 71 downwardly to reposition the valve block 60 into theposition shown in FIG. 3. Thus air is exhausted from chamber 32 and allof the incoming air is directed gage the flange 12 as shown in phantomlines in FIG.

The embodiment of FIG. 6 varies from the preferred embodiment in twoimportant aspects. First, the hollow central member a is rigidly securedto the cylinder 22a, rather than being detachably secured thereto as inthe preferred embodiment. In all other respects the driving mechanismand air supply are identical with the preferred embodiment. The secondmodified feature is in the means aligning the central member 10a and thedriven tube or casing T. In this embodiment a separate collar body a isprovided with anupper recess 101,

into chamber 34. The incoming air thus pushes against the underside ofthe piston 28 to raise the ram upwardly. Just prior to the pistonreaching the top of the cylinder 22, the lower cam 68 engages the valveactuator 70 to reposition the valve block into the position shown inFIG. 4. In this position air enters both the chamber 32 and the chamber34 cushioning the upward movement of the piston and again begins topropel the ram downwardly.

An important feature of this invention is the provision of a hollowcentral member through which a drill pipe 74 (shown only in FIG. 2 forbrevity) or the like can be inserted to inject drilling fluid underpressure down through the driven tube. The fluid and freed mud isdischarged through a discharge port 75.

As best shown in FIG. 1, the cylinder 22 can be positioned to drivethe'central member 10 upwardly. In this position the cams 66 and 68 areadjusted to cushion the downward impact of the ram 18 and to allow fullimpact in the upward direction. The .cylinder in this posia lower recess102, and a pipe connector 100 for removing drilling mud from within thetube T. The central member and tube fit respectively in the recesses andabut against a central flange 102. In this embodiment the lower flange14 is eliminated and the ram impacts directly against the collar body20a. The surfaces between the recesses and the central member and tubingmay be threaded if desired to allow the tubing to be moved upwardly asis the common practice. In operation the modified form of the apparatusis basically identical with that of the preferred form and furtherdetails are not believed necessary. As shown the collar body hasjustbeen impacted by the ram 18 and has slid its end rests on the centralflange 103 prior to the next impact. v 7 Y The embodiment of FIG. 7includes a hollow'c'entral member having an enlargement 82 at its lowerend. A ram 84 impacts against the upper surface of' the enlargement. Theupper end of the hollow central member is provided with an internalshoulder 86 that abuts against the upper surface of the tube 88beingldriven into the ground. A piston 89 rides in a cylinder 90 thatsurrounds the hollow central member and is connected to the ram 84:bypiston rods 91. The piston rods pass through bushings 92 provided inopenings in the lower wall'of the cylinder. The cylinder, piston, andair-control valve 92 otherwise operate as in FIG. 1. j

-A urethane-ring 96- seals the lower end of the cylinder. A secondurethane ring 97 seals the upper end of the cylinder in style A. Instyle A the cylinderis carried on a shoulder 9.8 on the outside of thehollow central -member. In style B a threaded connection 99 holds thecylinder on the hollow central member.

. Style A is used for driving casing down into the ground. Style B isfor driving casing out of the ground but generally should not be used inview of the resulting severe impact loading on the cylinder and aircontrol valve.

, While the preferred forms ofthe invention have been illustrated anddescribed, variations and modifications thereof will be apparent to oneskilled in the art. Accordingly,the invention is not to be limited tothe preferred embodiments illustrated, but rather is to be limited onlyby a literal interpretation of the-claims ap-.

meansat the lower end of the central member for aligning said centralmember with the casing to be driven an'd adapted to be impacted by saidram axially of said centralrnember for downward movement, thus forcingthe casing downwardly, and air supply means for delivering air to saidcylinder in a prearranged sequence to propel the ram downwardly to drivethe casing into the ground. '5 I 1 2. Apparatus of claim 1, saidcylinder and central memberforming a chamber therebetween to receive theair, said piston having seals engaging both the cylinder and thecentralmember and mounted for reciprocation in thechamber, said air supplymeans including means for deliveringair to either side of the piston inthe chamber.

3. Apparatus for driving a casing and permitting the casing to becleaned out while being driven, comprising a hollow central memberhaving an axial opening therethrough, a driving mechanism surroundingsaid central member. said driving mechanism including a cylinder axiallyslidably mounted on said central member and a piston surrounding saidcentral member, means for limiting said sliding movement, piston rodmeans secured to said piston, and ram means secured to said piston rodmeans for movement with said piston, means for locating the hollowcentral member with. said casing,

said driven casing, and air supply means for delivering air to saidcylinder in a prearranged sequence to propel the ram axially to drivethe casing axially.

4. The apparatus of claim 3, said impact receiving and transferringmeans including means on said hollow central member for engagement bysaid ram and means on said hollow central member for providing drivingengagement with said driven casing.

5. The apparatus of claim 3, said means for transferring the impact tosaid driven casing including a horizontal surface engageable with acorresponding horizontal surface on the casing being driven.

6. Apparatus for driving a tube and permitting the tube to be cleanedout while being driven, comprising a hollow central member having anaxial opening therethrough, a driving mechanism surrounding said centralmember, said driving mechanism including a cylinder and pistonsurrounding said central member, said cylinder being slidably mounted onsaid central member for limited axial movement, a piston rod secured atone end to said piston, and a ram secured to the opposite end of thepiston rod, said driving mechanism including a longitudinal guide barfixed against movement relative to said cylinder, said ram including abore for slidably receiving said guide bar whereby the ram is precludedfrom moving around the central member relative to said cylinder, meansat the lower end of the central member for aligning said central memberwith the tube to be driven and for receiving axial impact from said ramfor forcing the tube downwardly, and air supply means for delivering airto said cylinder in a prearranged sequence to propel the ram downwardlyto drive the tube into the ground.

7. Apparatus for driving a tube and permitting the tube to be cleanedout while being driven, comprising a' hollow central member. a drivingmechanism surrounding said central member, said driving mechanismincluding a cylinder and piston surrounding said central member, apiston rod secured at one end to said piston. and a ram secured to theopposite end of the piston rod. means at the lower end of the centralmember for aligning said central member with the tube to be driven andadapted to be impacted by said ram for forcing the tube downwardly. andair supply means for delivering air to said cylinder in a prearrangedsequence to propel the ram downwardly to drive the tube into the ground,said cylinder and central member forming a chamber therebetween toreceive the air, said piston having seals engaging both the cylinder andthe central member and mounted forreciprocation in the chainbehsaid airsupply means in'cludingjmeans for delivering air to either side of thepiston in. the chamber, said air supplying means further including acontrol rod having upper and lower cams, an air valve for directing airsimultaneously into the top of said cylinder below said piston. orsolely into the bottom of said cylinder, the crosssectional area of thepiston being greater on its, top surface than on its bottom surface sothat air delivered simultaneously to top and, bottom moves. the pistondownwardly, actuator means engageable with said cams for positioningsaidair valve into'its various positions, said cams being so positioned thatthe valve is movedto an alternate position prior to;completio n of thepiston upstroke so as to avoidundue-impact against the upperend of thecylinder. I i

8. Apparatus for driving a tube and permitting the tube to be cleanedout while beingdriven. comprising a hollow central member, a drivingmechanism surrounding said central member, said driving mechanismincluding a cylinder and piston surrounding saidcentral member, a pistonrod secured at one end to said piston, and a ram secured to the oppositeend of the piston rod, means at the lower end of the central member foraligning said central member with the tube to be driven and adapted tobe impacted by said ram for forcing the tube downwardly, and air supplymeans for delivering air to said cylinder in a prearranged sequence topropel the ram downwardly to drive the tube into the ground, saidimpacting and aligning means including a collar body having an uppersurface for receiving the impact of said ram, an upper bore forreceiving said central member, and a lower bore for receiving saiddriven tube, and means abutting the ends of the tube and central memberfor transferring the impact to the driven tube.

9. Apparatus for driving a tube and permitting the tube to be cleanedout while being driven, comprising a hollow central member, a drivingmechanism surrounding said central member, said driving mechanismincluding a cylinder and piston surrounding said central member, apiston rod secured at one end to said piston, and a ram secured to theopposite end of the piston rod, means at the lower end of the centralmember for aligning said central member with the tube to be driven andadapted to be impacted by said ram for forcing the tube downwardly, andair supply means for delivering air to said cylinder in a prearrangedsequence to propel the ram downwardly to drive the tube into the ground,said impacting and aligning means including interior threads on saidcentral member, exterior threads on said driven tube and a recess on theend of said tube in engagement with said central member for receivingimpact therefrom, said central member including a rigid impact of saidram.

10. The apparatus of claim"7,fsaid driving mechanism I including alongitudinal'guide bar 'fix'edagainst movement relative to saidcylinder. said ram including a bore for slidably receiving said guidebarwhereby the ram is precluded from moving around the central memberrelative to said cylinder".

11. Apparatus for driving a tube and permitting the tube to be cleanedout while being driven, comprising a hollow central member,. adriving-mechanism surrounding said central member, said drivingmechanism including a cylinder and piston surrounding said centralmember, piston rod means secured to said piston, and ram means securedto said piston rod means for movement with said piston, means forlocating the hollow central memberl with said tube in proper alignmentfor driving the tube, means for receiving impact blows from saidramfortransferring 'the impact to said driven tube; and air supply means fordelivering air to said cylinder in a prearranged sequence'tto propel theram downwardly to drive the tube into the ground, said impact receivingand transferring means including a rigid flange fixedaon the lower endof the central member and said 'loca'ting-rneans including threadsinterconnecting the-hollo'w central member with-said driven tubel: i

ml'Z. Apparatus for driving a tube and permitting the driving the tube.means for receiving impact 'blows from-said ram for transferring theimpact to said driven tube to be cleaned out while beingidriven,comprising a hollow central member, a driving mechanism surrounding saidcentral member, said driving mechanism including a cylinder and pistonsurrounding said central member, piston rod means secured to saidpiston, and ram means secured tosaid piston rod means for movement withsaid piston, means. for locating the hollow central member with saidtube in proper alignment for driving the tube, means for receivingimpact blows from said ramfor transferring the impact to said driventube, and air supply means for delivering air to said cylinder in aprearranged sequence to propel the ram downwardly to drive the tube intothe ground, said impact receiving and transferring means including meanson said hollow central member for engagement by said ram and means onsaid hollow central member for providing driving engagement with saiddriven tube, said ram engaged meansincluding an enlargement formed onthe lower end of said-central member, said means for providing drivingengagement-with said-driven tube includingan internal abutment on theupper end of said hollow central member. Tl

1. Apparatus for driving a casing and permitting the casing to be cleaned out while being driven, comprising a hollow central member having a straight, large axial opening adapted for receiving rods or the like, a driving mechanism surrounding said central member, said driving mechanism including a cylinder axially slidably mounted on said central member and a piston surrounding said central member, means on said central member for limiting said sliding movement of said cylinder, a piston rod secured at one end to said piston, and a ram secured to the opposite end of the piston rod, means at the lower end of the central member for aligning said central member with the casing to be driven and adapted to be impacted by said ram axially of said central member for downward movement, thus forcing the casing downwardly, and air supply means for delivering air to said cylinder in a prearranged sequence to propel the ram downwardly to drive the casing into the ground.
 2. Apparatus of claim 1, said cylinder and central member forming a chamber therebetween to receive the air, said piston having seals engaging both the cylinder and the central member and mounted for reciprocation in the chamber, said air supply means including means for delivering air to either side of the piston in the chamber.
 3. Apparatus for driving a casing and permitting the casing to be cleaned out while being driven, comprising a hollow central member having an axial opening therethrough, a driving mechanism surrounding said central member, said driving mechanism including a cylinder axially slidably mounted on said central member and a piston surrounding said central member, means for limiting said sliding movement, piston rod means secured to said piston, and ram means secured to said piston rod means for movement with said piston, means for locating the hollow central meMber with said casing, means for receiving impact blows from said ram axially of said central member for transferring axial impact to said driven casing, and air supply means for delivering air to said cylinder in a prearranged sequence to propel the ram axially to drive the casing axially.
 4. The apparatus of claim 3, said impact receiving and transferring means including means on said hollow central member for engagement by said ram and means on said hollow central member for providing driving engagement with said driven casing.
 5. The apparatus of claim 3, said means for transferring the impact to said driven casing including a horizontal surface engageable with a corresponding horizontal surface on the casing being driven.
 6. Apparatus for driving a tube and permitting the tube to be cleaned out while being driven, comprising a hollow central member having an axial opening therethrough, a driving mechanism surrounding said central member, said driving mechanism including a cylinder and piston surrounding said central member, said cylinder being slidably mounted on said central member for limited axial movement, a piston rod secured at one end to said piston, and a ram secured to the opposite end of the piston rod, said driving mechanism including a longitudinal guide bar fixed against movement relative to said cylinder, said ram including a bore for slidably receiving said guide bar whereby the ram is precluded from moving around the central member relative to said cylinder, means at the lower end of the central member for aligning said central member with the tube to be driven and for receiving axial impact from said ram for forcing the tube downwardly, and air supply means for delivering air to said cylinder in a prearranged sequence to propel the ram downwardly to drive the tube into the ground.
 7. Apparatus for driving a tube and permitting the tube to be cleaned out while being driven, comprising a hollow central member, a driving mechanism surrounding said central member, said driving mechanism including a cylinder and piston surrounding said central member, a piston rod secured at one end to said piston, and a ram secured to the opposite end of the piston rod, means at the lower end of the central member for aligning said central member with the tube to be driven and adapted to be impacted by said ram for forcing the tube downwardly, and air supply means for delivering air to said cylinder in a prearranged sequence to propel the ram downwardly to drive the tube into the ground, said cylinder and central member forming a chamber therebetween to receive the air, said piston having seals engaging both the cylinder and the central member and mounted for reciprocation in the chamber, said air supply means including means for delivering air to either side of the piston in the chamber, said air supplying means further including a control rod having upper and lower cams, an air valve for directing air simultaneously into the top of said cylinder below said piston, or solely into the bottom of said cylinder, the cross-sectional area of the piston being greater on its top surface than on its bottom surface so that air delivered simultaneously to top and bottom moves the piston downwardly, actuator means engageable with said cams for positioning said air valve into its various positions, said cams being so positioned that the valve is moved to an alternate position prior to completion of the piston upstroke so as to avoid undue impact against the upper end of the cylinder.
 8. Apparatus for driving a tube and permitting the tube to be cleaned out while being driven, comprising a hollow central member, a driving mechanism surrounding said central member, said driving mechanism including a cylinder and piston surrounding said central member, a piston rod secured at one end to said piston, and a ram secured to the opposite end of the piston rod, means at the lower end of the central member for aligning said central member with the tube to be driven And adapted to be impacted by said ram for forcing the tube downwardly, and air supply means for delivering air to said cylinder in a prearranged sequence to propel the ram downwardly to drive the tube into the ground, said impacting and aligning means including a collar body having an upper surface for receiving the impact of said ram, an upper bore for receiving said central member, and a lower bore for receiving said driven tube, and means abutting the ends of the tube and central member for transferring the impact to the driven tube.
 9. Apparatus for driving a tube and permitting the tube to be cleaned out while being driven, comprising a hollow central member, a driving mechanism surrounding said central member, said driving mechanism including a cylinder and piston surrounding said central member, a piston rod secured at one end to said piston, and a ram secured to the opposite end of the piston rod, means at the lower end of the central member for aligning said central member with the tube to be driven and adapted to be impacted by said ram for forcing the tube downwardly, and air supply means for delivering air to said cylinder in a prearranged sequence to propel the ram downwardly to drive the tube into the ground, said impacting and aligning means including interior threads on said central member, exterior threads on said driven tube and a recess on the end of said tube in engagement with said central member for receiving impact therefrom, said central member including a rigid flange adjacent the lower end thereof for receiving the impact of said ram.
 10. The apparatus of claim 7, said driving mechanism including a longitudinal guide bar fixed against movement relative to said cylinder, said ram including a bore for slidably receiving said guide bar whereby the ram is precluded from moving around the central member relative to said cylinder.
 11. Apparatus for driving a tube and permitting the tube to be cleaned out while being driven, comprising a hollow central member, a driving mechanism surrounding said central member, said driving mechanism including a cylinder and piston surrounding said central member, piston rod means secured to said piston, and ram means secured to said piston rod means for movement with said piston, means for locating the hollow central member with said tube in proper alignment for driving the tube, means for receiving impact blows from said ram for transferring the impact to said driven tube, and air supply means for delivering air to said cylinder in a prearranged sequence to propel the ram downwardly to drive the tube into the ground, said impact receiving and transferring means including a rigid flange fixed on the lower end of the central member and said locating means including threads interconnecting the hollow central member with said driven tube.
 12. Apparatus for driving a tube and permitting the tube to be cleaned out while being driven, comprising a hollow central member, a driving mechanism surrounding said central member, said driving mechanism including a cylinder and piston surrounding said central member, piston rod means secured to said piston, and ram means secured to said piston rod means for movement with said piston, means for locating the hollow central member with said tube in proper alignment for driving the tube, means for receiving impact blows from said ram for transferring the impact to said driven tube, and air supply means for delivering air to said cylinder in a prearranged sequence to propel the ram downwardly to drive the tube into the ground, said locating means including a collar body having an upper bore for receiving said central member and a lower bore for receiving said driven tube, said impact receiving and transferring means including means on said collar abutting the ends of the driven tube and the central member for transferring impact to the driven tube.
 13. Apparatus for driving a tube and permitting the tube to be cleaned out while being driven, comprising a hollow central member, a drIving mechanism surrounding said central member, said driving mechanism including a cylinder and piston surrounding said central member, piston rod means secured to said piston, and ram means secured to said piston rod means for movement with said piston, means for locating the hollow central member with said tube in proper alignment for driving the tube, means for receiving impact blows from said ram for transferring the impact to said driven tube, and air supply means for delivering air to said cylinder in a prearranged sequence to propel the ram downwardly to drive the tube into the ground, said impact receiving and transferring means including means on said hollow central member for engagement by said ram and means on said hollow central member for providing driving engagement with said driven tube, said ram engaged means including an enlargement formed on the lower end of said central member, said means for providing driving engagement with said driven tube including an internal abutment on the upper end of said hollow central member. 